Tunnel furnace, kiln, oven, and the like



Patented Mar. 3,1, 1925.

UNITED gSTATES,

i 1,531,279 PATENT oFFIcE.-

HENRI FRANCART, or ToNGnns, BELGIUM.

TUNNEL FUnNAcE, xiLN, ovnN, AND THE 1.11111.

Application IedJune 24, 1920,` Serial No. 391,512. Renewed February 21, 1925.

(GRANTED Unmnnmm: rnovIsIoN's'orrHE Aci: or Manon s, 1921, 41 sur. L., 1313.)

Tongres, Belgium, have invented certainy new and useful Improvements in or ,Relating to Tunnel Furnaces, Kilns,"Ovens, and the like (for which I have filed an applica,-y tion in England, December 19, 1918, Patent No. 166,198), of which thefollowing is a specification. l

The present invention relates to vtunnel ovens. f

In a well constructedtunnel oven, the articles under treatmentare always, in the coolingzone, at a higher temperature thanl the stationary faces of thewalls, whilst in the preheatingv zone -they arealways-at-a lower temperature than at thestationary;

walls surrounding them. v y l For the gaseous mass contained linj'the oven, there` is therefore ineach ysection of theroven an ascensional forcejdue to the difference in density ofthe gaseous mediumk in contact with one or the other solid body. The object of the presentinvention is to utilize this force in such `a way asto auto-w matically create a gaseous circulation in orderv to obtain more economical working and a better output. l

v The invention is realized by `forming one or two inclined passages passing successively.

through the articles under treatment and along the vertical walls, the pitchof the iny clined passage or passages being such that the ascensional forces cause thelongitudina-l desiredy displacements.

vForone Vand the same displacement, the` inclined pitch will, inV the preheating zone, be inverse'tothat in the cooling zone. o .This automatic displacement may be used in combination .with a. draught apparatus yin order to conduct the gases to the mouth or entrance of the tunnel oven.

The helical passageorrinclined passages may be made of different material, and may approach more or less the theoretical helical pitch. With a view of obtaining the maximum effect, it is necessary that'each portion of the helix should beso arranged as to localize radiation.

In a. tunnel oven this arrangement may be used over the whole length, or over a portion only in flame ovens or in ovens of the Inutile type.

According to one method of construction, the heating and cooling zones are formed of a number of compartments, higher and broader than is necessary for the passage of the trucks loaded with the goods to be treated, lthe separating partitions leaving an opening for the'passage of the goods.

From the entrance of the tunnel oven towards the outlet, eachchamber, in the preheating zone, is in communication at the top with the bottom ofthe adjoining one, this communication being eHected along the wall of the passage..

In the cooling zone, on the contrary, the bottom of each chamber is in communication along the wall with the top of the following chamber. y v

The inclined passage formed by these passages and'th'e introduction into the oven in sections of theV goods to be treated-cause an automatic draught which ensures the regular and progressive treatment in each chamber.

The draught of the oven may also be increased by using the same process for the drying zone, care being taken to arrange the burners'in the bottom part of the passages along the walls.

If the oven is not very high, which would be the case in ovens for annealing metals, a. more or less inclined passage can be obtained by simply forming the partitions which separate the compartments by means of two vertical planes which intersect each other at an angle more'or less acute'n relation to. the centre of the oven. In the cooling zone the angle formed is directed towards the outlet of the oven and in the heating zone towards the entrance.

lThe accompanying Vdrawings show two constructional forms of the invention by way of example.

Figure 1 is a longitudinal section showing an elevation of the two zones of the tunnel oven.

` Figure 2 is a cross Vsection through the heating zone.

Figure 3, drawn to a reduced scale, is a section of a low annealing oven, while Figure 4 is a diagrammatic section plan thereof.

In the arrangement shown in Figs. 1 and 2 the trucks 1 successively traverse the two zones of the oven in the direction shown by the arrow. The upper region of the oven is traversed by vertical partitions 2, which divide the tunnel into compartments 2. Adjacent each wall of the oven and extending from the lower edges of thek ytransverse vertical partitions, are inclined partitions The lower part of these y inclined partitions fall immediately under the transverse partition adjacent the one from which it eX- tends. Extending along the inside of the inclined partitions arel longitudinal wallsL which have openings, as indicated by the numeral 5, leading from the main part of the oven into the conduit formed by the inclined partitions 3. F rom. this structure it \vi`llbe seen that there is formed by'means of the longitudinal wall 4,' the inclinedA partitions 3,' and the vertical partitions' 2 what might be called inclined passages. The gases entering into openings 5, either from the source of gas supply which may be any suitable source, or from the oven through the openings in the longitudinal Walls will be given a longitudinal motion by means of the inclined lpassage formed by the parti tion 3.

By means of the vertical partition an increased surface is provided for radiation and the localization of the heat. These partitions alsoaid in directing the heat to the objects that are being treated.

` In the preheating zone, each compartment is in communication at the top with the bottom of the following compartment in the direction of the outlet. In the cooling Zone, the contrary is the case. By arranging the articles to be treated in the fornr of successive sections 7 upon the trucks, the helical passage will thus be formed in inverse directions in the two Zones. i

In the preheating zone the gases entering through the openings' ascend first into the central part of the compartment between the partitions 2, traversing the goods and are then directed downwardly through the conduits formed by the inclined partitions 3 toward the bottom of the next compartment and so on. This action takes place on both sides of the oven, as indicated byarrows in Fig. 2.

The device shown and described in this application is merely the preheating and coolingparts of an oven, and describes that part of the oven which may be used in connection with the heating zone of a similar oven shown and described in applicants copendingapplication Serial No. 391,513.

In working order the gases therefore circulate automatically or by the aid of the draught ap-paratus from the cooling zone through the heating zone passing successive i use is preferably made of partitions G ar- A`ranged aecording to ftivo vertical planes interseoting each other in the axis of the oven, so that the gas imprisoned between them and ascending or descendingin the central portion will carry along the whole of the gaseous mass in the desired direction.

The arrows marked in full lines in Figure 4l indicate the'direction in which thetrucks travel; the -arrows in brokenA lines indicate the ,entrance of the air and the exit of the gases respectively.

vHaving now particularly described and ascertained the nature of my said invention, and in what manner the same is .to be performed, I declare that what I claim is:

l. In `a funnel oven, flanges extending across the interior of the oven, forming radiating surfaces and heat localizing spaces, diagonal flanges on each side of the oven extending from the lower part thereof to the first named flange.

2. In a tunnel oven, flanges extending across the interior thereof, forming radiating surfaces and heat localizing spaces, diagonal flanges on each side of the oven extending from the lower part thereof to the first named flanges, said diagonal flanges at one end of the oven s lanting in a direction opposite to those at the other end.

3. In a tunnel oven, flanges extending across the interior surface thereof, diagonal flangesconnecting the first named flanges to the lower part of the oven and longitudinal partitions joining the diagonal flanges and partly separating 4the main cavity of the oven from the conduit formed by the diagonal partitions.

4. In a tunnel oven` means extending across the inner surface thereof for the purpose of localizing the heat and increasing the surface of radiation and diagonal means extending from the first named means to the lower part of the oven and means connecting the lasty named means and forming therewith conduits to direct the product'of combustion to the upper part ofthe oven.

Intestimonv whereof I affix my signature in presence of two witnesses.

HENRI FR ANCART. Witnesses IsHoFFIN, G. .IZALEAN lll) 

